The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed.
In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling-down also produces a relatively high power dissipation value, which may be addressed by using low power dissipation devices such as complementary metal-oxide-semiconductor (CMOS) devices. CMOS devices have typically been formed with a gate oxide and polysilicon gate electrode. There has been a desire to replace the gate oxide and polysilicon gate electrode with a high-k gate dielectric and metal gate electrode to improve device performance as feature sizes continue to decrease. However, problems arise when integrating a high-k/metal gate feature in a CMOS process flow due to various factors such as incompatibility of materials, complex processes, and thermal budgets.
For example, polysilicon resistors have been widely used in conventional integrated circuit design, including for RC oscillators, current limitation resistance, ESD protect, RF post drivers, on-chip termination, impedance matching, etc. Also, polysilicon electronic fuses (eFuses) have also been widely used in conventional memory integrated circuit design. However, integrating high-k metal gate technology with these types of devices has been challenging. In some situations, the polysilicon resistors and polysilicon eFuses may exhibit a lower than desirable resistivity following fabrication (i.e., due to affects from gate replacement processing, such as gate fill and chemical mechanical polishing processes), and thus these devices may be ineffective for their intended function.
Accordingly, what is needed are semiconductor devices that address the above stated issues, and methods for making such semiconductor devices.